Born in Birmingham but brought up in New Zealand, Fay returned to the UK aged 15 just after the Second World War. After studying at St Andrews, she moved to London in the early 1950s, working for the Foreign Office and then in advertising. She began writing for radio and television in 1963 when she fell pregnant with her first child, producing plays for ITV and the BBC and writing three episodes of Upstairs Downstairs, including the first in 1971. In the end, she wrote over 70 scripts for television, including an adaptation of Pride & Prejudice in 1980. Her first novel was published in 1967 and was followed by over 30 others, including The Lives and Loves of a She-Devil which became a beloved BBC series. Fay died in Northampton, England on 4 January 2023, at the age of 91.